Biological testing has become an important tool in detecting and monitoring diseases. In the biological testing field, thermal cycling is used to amplify nucleic acids by, for example, performing PCR and other reactions. PCR in particular has become a valuable research tool with applications such as cloning, analysis of genetic expression, DNA sequencing, and drug discovery.
Recent developments in the field have spurred growth in the number of tests that are performed. One method for increasing the throughput of such biological testing is to provide real-time detection capability during thermal cycling. Real-time detection increases the efficiency of the biological testing because the characteristics of the samples can be detected while the sample well tray remains positioned in the thermal cycling device.
In a real-time detection system testing may be performed on multiple samples during a cycle of the testing device. With this type of system, light may be emitted from a light source to be absorbed and re-emitted as fluorescence by the biological sample(s) and ultimately may be detected or collected by a light detecting device such as a camera or CCD, for example. To assist in the focusing the light into the samples and collecting the light out of the samples toward detecting device, one or more lenses may be provided.
One of the drawbacks of conventional devices utilizing lens assemblies in conjunction with multiple sample testing devices is the complexity of the lens(es). It may often be desirable to have a lens for collimating light so that it may be properly aligned with a row or column of sample wells in a sample well tray. To further enhance the testing process, an additional lens assembly may be provided for focusing light more precisely within each of the sample wells. These focusing lens assemblies often may comprise a plurality of non-integral components.